homework help > math > calculus q&a board > topic: i have posted 3 times no one helped???...

Q BgQuestion:

      
Novice
Karma Points: 33
Respect (68%):
posted by  Mr. Cool Boy on 9/21/2009 12:46:19 AM  |  status: Closed  |  Earned Karma: 33

i have posted 3 times no one helped???

Course Textbook Chapter Problem Needs by
Calculus N/A N/A N/A 9/21/2009 at 9:00:00 AM
Question Details:

(1 pt) a. Estimate \int_1^{6} {2 \sqrt{x} - 1} dx using 5 left rectangles.  

b. Estimate \int_1^{6} {2 \sqrt{x} - 1 } dx using 5 right rectangles.  

c. Estimate \int_1^{6} {2 \sqrt{x} - 1 } dx using 5 midpoint rectangles.  

education should be free
Bonus Point Alert! Earn +4 additional karma points for helping this gold member.

AAnswers:

Answer Question Ask for clarification
Oracle
Karma Points: 14,954
posted by Grace on 9/21/2009 2:01:37 AM  |  status: Live
Asker's Rating: Lifesaver   
Response Details:
Riemann sums method:

Σ (base)(height) = ΣΔx f(c) where Δx = (b - a) / n and "c" are the endpoints you plug in

f(x) is given by the function in the integral
Δx = (6 - 1)/5 = 5/5 = 1

a) left endpoints are: 1, 2, 3, 4, 5
ΣΔxf(x) = (1)[(2√(1) - 1) + (2√(2) - 1) + (2√(3) - 1) + (2√(4) - 1) + (2√(5) - 1)] = 11.76

b) right endpoints are: 2, 3, 4, 5, 6
ΣΔxf(x) = (1)[(2√(2) - 1) + (2√(3) - 1) + (2√(4) - 1) + (2√(5) - 1) + (2√(6) - 1)] = 14.66

c) midpoints are: 1.5, 2.5, 3.5, 4.5, 5.5
ΣΔxf(x) = (1)[(2√(1.5) - 1) + (2√(2.5) - 1) + (2√(3.5) - 1) + (2√(4.5) - 1) + (2√(5.5) - 1)] = 13.29
“The idea of education has been so tied to schools, universities, and professors that many assume there is no other way, but education is available to anyone within reach of a library, a post office, or even a newsstand.” - Louis L'Amour, Education of a Wandering Man

"I need the world to last another century and a half, not just see me to happy old age. " - David Mitchell, Washington Post Interview (Aug. 2004)  
 
I took the time to help you, please take the time to help me. Send some good karma my way.

Rules of Thumbs for New Posters:
1. Post the complete question. Never just ask: How do you do problem 10 in Stewart? or you will not get help.
2. Don't post multiple questions in one post. Only exception: Followup posts to clarify the original question or to understand answers.
3. Always rate. Rate the best answer. This may not always be the answer given by the first poster. Do not give good karma to posts that give only answers w/o explanations. Note that even posts that are unrelated to the questions must be rated, even if it is N/A, or they will affect your respect score.
4. Cutting & pasting solutions of other posters is karma point abuse. Work to maintain board integrity!
Answer Question Ask for clarificarion
Ask New Question

Join Cramster's Community

Cramster.com brings together students, educators and subject enthusiasts in an online study community. With around-the-clock expert help and a community of over 100,000 knowledgeable members, you can find the help you need, whenever you need it. Join for free today » How Cramster is different from tutoring »

Need Help In

Useful Links